I'm enjoying it. I think things are starting slowly, but that is only to be expected when the PCs start out not knowing each other. And a part of it may be my fault, for bringing a world-weary loner PC to the table without thinking how to get him interacting with the group. I'm trying to get him involved without metagaming, but I do find myself stretching at times. Still, it's obvious that you've planned carefully and have an intriguing, solid idea where the campaign is going to go. I'm certainly not going to drop out any time soon.
I think that Ghostknight is right in that a PbP game can get really bogged down in minutae if it includes many combat scenes as a tabletop game would. It only takes one player to be a day or two late with their IC posts and things can really start to drag. Having said that, you do need to have occasional combats, but perhaps save the really detailed, round-by-round stuff for major, important scenes.